Who was the winner of Stage 9 when then general classification was Danilo Di Luca?
CREATE TABLE table_13639 (
    "Stage" text,
    "Winner" text,
    "General classification" text,
    "Points classification" text,
    "Mountains classification" text,
    "Young rider classification" text
)
SELECT "Winner" FROM table_13639 WHERE "General classification" = 'danilo di luca' AND "Stage" = '9'
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: Who was the winner of Stage 9 when then general classification was Danilo Di Luca? ### Input: CREATE TABLE table_13639 (
    "Stage" text,
    "Winner" text,
    "General classification" text,
    "Points classification" text,
    "Mountains classification" text,
    "Young rider classification" text
) ### Response: SELECT "Winner" FROM table_13639 WHERE "General classification" = 'danilo di luca' AND "Stage" = '9'