user: Question: Which date was the Memorial Tournament held on, when Payne Stewart was runner-up?
Columns: ['Date', 'Tournament', 'Winning score', 'Margin of victory', 'Runner(s)-up']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['3 Jun 1984', 'Kemper Open', '–8 (68-68-71-73=280)', '5 strokes', "Mark O'Meara"]
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Tournament" = 'Memorial Tournament' AND "Runner(s)-up" = 'Payne Stewart';