What crew chief has an owner name Jack Roush and driver Greg Biffle?
CREATE TABLE table_15221 (
    "Team" text,
    "Car(s)" text,
    "Driver(s)" text,
    "Primary Sponsor(s)" text,
    "Owner(s)" text,
    "Crew Chief" text
)
SELECT "Crew Chief" FROM table_15221 WHERE "Owner(s)" = 'jack roush' AND "Driver(s)" = 'greg biffle'
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: What crew chief has an owner name Jack Roush and driver Greg Biffle? ### Input: CREATE TABLE table_15221 (
    "Team" text,
    "Car(s)" text,
    "Driver(s)" text,
    "Primary Sponsor(s)" text,
    "Owner(s)" text,
    "Crew Chief" text
) ### Response: SELECT "Crew Chief" FROM table_15221 WHERE "Owner(s)" = 'jack roush' AND "Driver(s)" = 'greg biffle'