CREATE TABLE table_16945 ("Date" TEXT, "Tournament" TEXT, "Location" TEXT, "Purse (  $  ) " FLOAT, "Winner" TEXT, "Score" TEXT, "1st Prize (  $  ) " FLOAT)

what is the minimum purse( $ ) where tournament is ko olina senior invitational
SELECT MIN("Purse( $ )") FROM table_16945 WHERE "Tournament" = 'Ko Olina Senior Invitational'
SELECT MIN("Purse( $ )") FROM "table_16945" WHERE "Tournament" = 'Ko Olina Senior Invitational'