What is the rank of the airport with freight ( metric tonnes ) of 255121?
CREATE TABLE table_13836704_6 (
    rank VARCHAR,
    freight___metric_tonnes__ VARCHAR
)
SELECT rank FROM table_13836704_6 WHERE freight___metric_tonnes__ = 255121
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 is the rank of the airport with freight ( metric tonnes ) of 255121? ### Input: CREATE TABLE table_13836704_6 (
    rank VARCHAR,
    freight___metric_tonnes__ VARCHAR
) ### Response: SELECT rank FROM table_13836704_6 WHERE freight___metric_tonnes__ = 255121