user: Question: What game site had a result at L 21–13?
Columns: ['Week', 'Date', 'Opponent', 'Result', 'Game site', 'Record', 'Attendance']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'September 16, 1937', 'New York Giants', 'W 13–3', 'Griffith Stadium', '1–0', '25,000']
SQL:

assistant: SELECT "Game site" FROM "Table" WHERE "Result" = 'L 21–13';