Who had a transfer fee of released and played the position of DF?
CREATE TABLE table_name_30 (
    player VARCHAR,
    transfer_fee VARCHAR,
    pos VARCHAR
)
SELECT player FROM table_name_30 WHERE transfer_fee = "released" AND pos = "df"
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 had a transfer fee of released and played the position of DF? ### Input: CREATE TABLE table_name_30 (
    player VARCHAR,
    transfer_fee VARCHAR,
    pos VARCHAR
) ### Response: SELECT player FROM table_name_30 WHERE transfer_fee = "released" AND pos = "df"