user: Question: What margin was in after 1981, and was Roberto De Vicenzo runner-up?
Columns: ['Year', 'Championship', 'Winning score', 'Margin', 'Runner(s)-up']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1981.0, "PGA Seniors' Championship", '−7 (68-72-68-73=281)', '2 strokes', 'Arnold Palmer']
SQL:

assistant: SELECT "Margin" FROM "Table" WHERE "Year" > 1981.0 AND "Runner(s)-up" = 'Roberto De Vicenzo';