Answer the following question: Information:  - The United States Congress is the bicameral legislature of the federal government of the United States consisting of two chambers: the Senate and the House of Representatives. The Congress meets in the Capitol in Washington, D.C. Both senators and representatives are chosen through direct election, though vacancies in the Senate may be filled by a gubernatorial appointment. Members are usually affiliated to the Republican Party or to the Democratic Party, and only rarely to a third party or as independents. Congress has 535 voting members: 435 Representatives and 100 Senators. The House of Representatives has six non-voting members in addition to its 435 voting members. These members can, however, sit on congressional committees and introduce legislation. These members represent Washington, D.C., Puerto Rico, American Samoa, Guam, the Northern Mariana Islands and the U.S. Virgin Islands.  - Joseph Ambrose `` Joe '' Sestak , Jr. ( born December 12 , 1951 ) is an American politician and former U.S. Navy three - star admiral . A member of the Democratic Party , he represented Pennsylvania 's 7th congressional district in the United States House of Representatives from 2007 to 2011 and was the Democratic nominee for the United States Senate in 2010 , losing to Republican nominee Pat Toomey . He was and remains the highest - ranking military official ever elected to the United States Congress . Sestak was a member of the United States Navy for over 30 years . He served as the Director for Defense on the National Security Council staff under President Bill Clinton and held a series of operational commands , including commanding the USS George Washington carrier strike group during combat operations in the Persian Gulf and Indian Ocean in 2002 . Sestak was elected to the House of Representatives in 2006 and re-elected in 2008 . He declined to run for re-election in 2010 , instead running for the Senate . He faced incumbent Senator Arlen Specter ( who had recently switched from the Republican Party ) in the Democratic primary and defeated him 54 % to 46 % . In the general election , he was narrowly defeated by Republican nominee Pat Toomey , 51 % to 49 % , a margin of 80,229 votes out of almost 4 million cast . He is seeking a rematch with Toomey in the 2016 election .  - A congress is a formal meeting of the representatives of different nations, constituent states, independent organizations (such as trade unions), or groups.  - Patrick Joseph "Pat" Toomey (born November 17, 1961) is an American businessman and politician. He is the junior United States Senator for Pennsylvania, in office since 2011, and a member of the Republican Party. Previously, Toomey served as a United States Representative for three terms, from 1999 to 2005, but he did not seek a fourth term in compliance with a term limits pledge he had made while running for office in 1998.  - The United States Senate is the upper chamber of the United States Congress which, along with the House of Representatives, the lower chamber, composes the legislature of the United States.  - The United States House of Representatives is the lower chamber of the United States Congress which, along with the Senate, composes the legislature of the United States.  - Pennsylvania (Pennsylvania German: "Pennsylvaani"), officially the Commonwealth of Pennsylvania, is a state located in the northeastern and Mid-Atlantic regions of the United States. The Appalachian Mountains run through its middle. The commonwealth borders Delaware to the southeast, Maryland to the south, West Virginia to the southwest, Ohio to the west, Lake Erie and the Canadian province of Ontario to the northwest, New York to the north, and New Jersey to the east.  - Guam (or ; Chamorro: ; formally the Territory of Guam) is an unincorporated and organized territory of the United States. Located in the western Pacific Ocean, Guam is one of five American territories with an established civilian government. The capital city is Hagåtña, and the most populous city is Dededo. In 2015, 161,785 people resided on Guam. Guamanians are American citizens by birth. Guam has an area of and a population density of 297/km² (770/sq mi). It is the largest and southernmost of the Mariana Islands, and the largest island in Micronesia. Among its municipalities, Mongmong-Toto-Maite has the highest density at 1,425/km² (3,691/sq mi), whereas Inarajan and Umatac have the lowest density at 47/km² (119/sq mi). The highest point is Mount Lamlam at above sea level.    What entity does 'joe sestak' has the relation 'position held' with?
Answer:
united states representative