CREATE TABLE table_13639 ("Stage" TEXT, "Winner" TEXT, "General classification" TEXT, "Points classification" TEXT, "Mountains classification" TEXT, "Young rider classification" TEXT)

Who was the winner of Stage 9 when then general classification was Danilo Di Luca?
SELECT "Winner" FROM table_13639 WHERE "General classification" = 'danilo di luca' AND "Stage" = '9'
SELECT "Winner" FROM "table_13639" WHERE "General classification" = 'danilo di luca' AND "Stage" = '9'