user: Question: Opponent of Chicago Bears involved what date?
Columns: ['Week', 'Date', 'Opponent', 'Result', 'Venue', 'Attendance']
Types: ['real', 'text', 'text', 'text', 'text', 'real']
Sample row: [1.0, 'September 19, 1965', 'at Pittsburgh Steelers', 'W 41-9', 'Pitt Stadium', 38383.0]
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Opponent" = 'Chicago Bears';