user: Question: When did the 1966 Cleveland Browns play the Green Bay Packers?
Columns: ['Week', 'Date', 'Opponent', 'Result', 'Attendance']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'September 11, 1966', 'at Washington Redskins', 'W 38–14', '48,643']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Opponent" = 'Green Bay Packers';