list each code not associated to a year .
CREATE TABLE table_203_248 (
    id number,
    "code" text,
    "year" number
)
SELECT "code" FROM table_203_248 WHERE "year" IS NULL
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: list each code not associated to a year . ### Input: CREATE TABLE table_203_248 (
    id number,
    "code" text,
    "year" number
) ### Response: SELECT "code" FROM table_203_248 WHERE "year" IS NULL