user: Question: Which Winning score has a Margin of victory of 1 stroke, and a Date of 21 Jun 1981?
Columns: ['Date', 'Tournament', 'Winning score', 'Margin of victory', 'Runner(s)-up']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['26 Aug 1972', 'Viyella PGA Championship', '–9 (71-72-68-68=279)', '3 strokes', 'Peter Oosterhuis']
SQL:

assistant: SELECT "Winning score" FROM "Table" WHERE "Margin of victory" = '1 stroke' AND "Date" = '21 Jun 1981';