user: Question: What date did the Chicago Bears beat the Green Bay Packers 31-20?
Columns: ['Year', 'Date', 'Winner', 'Result', 'Loser', 'Attendance', 'Location']
Types: ['real', 'text', 'text', 'text', 'text', 'real', 'text']
Sample row: [1950.0, 'Sunday, October 1', 'Green Bay Packers', '31–21', 'Chicago Bears', 24893.0, 'Green Bay']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Loser" = 'Green Bay Packers' AND "Location" = 'Green Bay';