user: Question: By how many strokes did Lema beat Jack Nicklaus?
Columns: ['Date', 'Tournament', 'Winning score', 'Margin of victory', 'Runner(s)-up']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Sep 30, 1962', 'Sahara Invitational', '–14 (69-67-66-68=270)', '3 strokes', 'Don January']
SQL:

assistant: SELECT "Margin of victory" FROM "Table" WHERE "Runner(s)-up" = 'Jack Nicklaus';