What is the county with an AA IHSAA class in ferdinand?
CREATE TABLE table_name_90 (
    county VARCHAR,
    ihsaa_class VARCHAR,
    location VARCHAR
)
SELECT county FROM table_name_90 WHERE ihsaa_class = "aa" AND location = "ferdinand"
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 county with an AA IHSAA class in ferdinand? ### Input: CREATE TABLE table_name_90 (
    county VARCHAR,
    ihsaa_class VARCHAR,
    location VARCHAR
) ### Response: SELECT county FROM table_name_90 WHERE ihsaa_class = "aa" AND location = "ferdinand"