What ship size had a cargo value of $31,750 in 2006?
CREATE TABLE table_42581 (
    "Ship size" text,
    "Cargo" text,
    "2004" text,
    "2005" text,
    "2006" text
)
SELECT "Ship size" FROM table_42581 WHERE "2006" = '$31,750'
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 ship size had a cargo value of $31,750 in 2006? ### Input: CREATE TABLE table_42581 (
    "Ship size" text,
    "Cargo" text,
    "2004" text,
    "2005" text,
    "2006" text
) ### Response: SELECT "Ship size" FROM table_42581 WHERE "2006" = '$31,750'