CREATE TABLE table_41543 ("Date" TEXT, "Tournament" TEXT, "Winning score" TEXT, "Margin of victory" TEXT, "Runner ( s ) -up" TEXT)

What date has yani tseng as the runner (s)-up?
SELECT "Date" FROM table_41543 WHERE "Runner(s)-up" = 'yani tseng'
SELECT "Date" FROM "table_41543" WHERE "Runner(s)-up" = 'yani tseng'