which kyu levels have only one color belt ?
CREATE TABLE table_203_392 (
    id number,
    "rank" text,
    "belt alternate 1" text,
    "belt alternate 2" text,
    "belt alternate 3" text,
    "belt alternate 4" text
)
SELECT "rank" FROM table_203_392 WHERE "belt alternate 2" 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: which kyu levels have only one color belt ? ### Input: CREATE TABLE table_203_392 (
    id number,
    "rank" text,
    "belt alternate 1" text,
    "belt alternate 2" text,
    "belt alternate 3" text,
    "belt alternate 4" text
) ### Response: SELECT "rank" FROM table_203_392 WHERE "belt alternate 2" IS NULL