user: Question: what is the minimum purse( $ ) where tournament is Ko Olina Senior Invitational
Columns: ['Date', 'Tournament', 'Location', 'Purse( $ )', 'Winner', 'Score', '1st Prize( $ )']
Types: ['text', 'text', 'text', 'real', 'text', 'text', 'real']
Sample row: ['Jan 12', 'Infiniti Senior Tournament of Champions', 'California', 350000.0, 'Al Geiberger (7)', '282 (-6)', 52500.0]
SQL:

assistant: SELECT MIN("Purse( $ )") FROM "Table" WHERE "Tournament" = 'Ko Olina Senior Invitational';