user: Question: What was the to par of the tournament that had Ken Duke as a runner-up?
Columns: ['Date', 'Tournament', 'Winning score', 'To par', 'Margin of victory', 'Runner-up']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Apr 22, 2007', 'Zurich Classic of New Orleans', '69-67-68-69=273', '−15', '3 strokes', 'Ken Duke']
SQL:

assistant: SELECT "To par" FROM "Table" WHERE "Runner-up" = 'Ken Duke';