Question: What year did Negro American League join?
SQL: SELECT MIN("Began in St. Louis") FROM "1-21564794-3" WHERE "League" = 'Negro American League';

Question: What year did the team who played at the Scottrade Center leave the city?
SQL: SELECT MIN("Left St. Louis") FROM "1-21564794-3" WHERE "Venue" = 'Scottrade Center';

Question: How may championships were won by the team that started in 1950?
SQL: SELECT "Championships in St. Louis" FROM "1-21564794-3" WHERE "Began in St. Louis" = 1950.0;

Question: How many championships were won for Arena Football?
SQL: SELECT "Championships in St. Louis" FROM "1-21564794-3" WHERE "Sport" = 'Arena Football';