user: Question: When is the latest game the bills had 21 first downs
Columns: ['Game', 'Date', 'Opponent', 'Result', 'Bills points', 'Opponents', 'Bills first downs', 'Record']
Types: ['real', 'text', 'text', 'text', 'real', 'real', 'real', 'text']
Sample row: [1.0, 'Sept. 16', 'at New England Patriots', 'Win', 31.0, 13.0, 23.0, '1–0']
SQL:

assistant: SELECT MAX("Game") FROM "Table" WHERE "Bills first downs" = 21.0;