Given the following context:  Seattle was awarded a Major League Baseball franchise, the Seattle Pilots, in 1969. The team played at Sick's Stadium in Mount Baker for one season before relocating to Milwaukee and becoming the Milwaukee Brewers. The city, county, and state governments sued the league and was offered a second expansion team, the Seattle Mariners, who began play at the Kingdome in 1977. The Mariners struggled in the stadium and moved to a purpose-built baseball stadium, T-Mobile Park (formerly Safeco Field), in 1999. The Mariners have never reached a World Series and only appeared in the MLB playoffs four times, all between 1995 and 2001, despite having Hall of Fame players and candidates like Ken Griffey Jr., Randy Johnson, Ichiro, and Alex Rodriguez. The team tied the all-time single regular season wins record in 2001 with 116 wins. Since 2001, the Mariners have failed to qualify for the playoffs—the longest active postseason drought in North American sports, at 17 seasons. From 1967 to 2008 Seattle was also home to a National Basketball Association (NBA) franchise: the Seattle SuperSonics, who were the 1978–79 NBA champions. The SuperSonics relocated to Oklahoma City and became the Oklahoma City Thunder for the 2008–09 season.The Major League Baseball All-Star Game was held in Seattle twice, first at the Kingdome in 1979 and again at Safeco Field in 2001. The NBA All-Star Game was also held in Seattle twice: the first in 1974 at the Seattle Center Coliseum and the second in 1987 at the Kingdome.Seattle also boasts two collegiate sports teams based at the University of Washington and Seattle University, both competing in NCAA Division I for various sports. The University of Washington's athletic program, nicknamed the Huskies, competes in the Pac-12 Conference, and Seattle University's athletic program, nicknamed the Redhawks, mostly competes in the Western Athletic Conference. The Huskies teams use several facilities, including the 70,000-seat Husky Stadium for football and the Hec Edmundson Pavilion for basketball and...  answer the following question:  What league will be bringing an expansion team in 2021 to the city that once housed the Seattle Supersonics?
A:
National Hockey League