user: Question: When did the W 20-19 happen?
Columns: ['Week', 'Date', 'Opponent', 'Result', 'Attendance']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'September 1, 1991', 'at Chicago Bears', 'L 10-6', '64,112']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Result" = 'W 20-19';