user: Question: What was the attendance when they played at Detroit Lions?
Columns: ['Week', 'Date', 'Opponent', 'Result', 'Attendance']
Types: ['real', 'text', 'text', 'text', 'real']
Sample row: [1.0, 'September 15, 1974', 'at New Orleans Saints', 'W 17-13', 65071.0]
SQL:

assistant: SELECT "Attendance" FROM "Table" WHERE "Opponent" = 'at Detroit Lions';