what rank has years until mandatory retirement of 6 years?
CREATE TABLE table_51685 (
    "Name" text,
    "Rank" text,
    "Years until mandatory retirement" text,
    "Appointed by" text,
    "Year appointed" real
)
SELECT "Rank" FROM table_51685 WHERE "Years until mandatory retirement" = '6 years'
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 rank has years until mandatory retirement of 6 years? ### Input: CREATE TABLE table_51685 (
    "Name" text,
    "Rank" text,
    "Years until mandatory retirement" text,
    "Appointed by" text,
    "Year appointed" real
) ### Response: SELECT "Rank" FROM table_51685 WHERE "Years until mandatory retirement" = '6 years'