What is the NOAA of the higher harmonics that have a Darwin of m sf?
CREATE TABLE table_4568 (
    "Higher harmonics" text,
    "Darwin" text,
    "Period" text,
    "Speed" text,
    "Doodson coefficients" text,
    "NOAA" text
)
SELECT "NOAA" FROM table_4568 WHERE "Darwin" = 'm sf'
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 NOAA of the higher harmonics that have a Darwin of m sf? ### Input: CREATE TABLE table_4568 (
    "Higher harmonics" text,
    "Darwin" text,
    "Period" text,
    "Speed" text,
    "Doodson coefficients" text,
    "NOAA" text
) ### Response: SELECT "NOAA" FROM table_4568 WHERE "Darwin" = 'm sf'