user: Question: What is the Date at Memorial Stadium • Minneapolis, MN, and an Opponent of Northwestern?
Columns: ['Date', 'Opponent', 'Site', 'Result', 'Attendance']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['09/27/1930', 'South Dakota State', 'Memorial Stadium • Minneapolis, MN', 'W48-0', '20,000']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Site" = 'Memorial Stadium • Minneapolis, MN' AND "Opponent" = 'Northwestern';