user: Question: Which Opponent has a Date of November 21, 1999?
Columns: ['Week', 'Date', 'Opponent', 'Result', 'Attendance']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'September 12, 1999', 'at Indianapolis Colts', 'L 31–14', '56,238']
SQL:

assistant: SELECT "Opponent" FROM "Table" WHERE "Date" = 'November 21, 1999';