In which round did Roy Salvadori won Class D and Alan Hutcheson won Class B?
CREATE TABLE table_24853015_1 (
    round VARCHAR,
    class_d_winner VARCHAR,
    class_b_winner VARCHAR
)
SELECT round FROM table_24853015_1 WHERE class_d_winner = "Roy Salvadori" AND class_b_winner = "Alan Hutcheson"
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: In which round did Roy Salvadori won Class D and Alan Hutcheson won Class B? ### Input: CREATE TABLE table_24853015_1 (
    round VARCHAR,
    class_d_winner VARCHAR,
    class_b_winner VARCHAR
) ### Response: SELECT round FROM table_24853015_1 WHERE class_d_winner = "Roy Salvadori" AND class_b_winner = "Alan Hutcheson"