what is the minimum of follow up years do each author have ?
CREATE TABLE table_204_597 (
    id number,
    "main author" text,
    "no. of patients" number,
    "duration of follow-up years" number,
    "linearized rate of infection" text,
    "actuarial freedom from infective endocarditis" text
)
SELECT MIN("duration of follow-up years") FROM table_204_597
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 minimum of follow up years do each author have ? ### Input: CREATE TABLE table_204_597 (
    id number,
    "main author" text,
    "no. of patients" number,
    "duration of follow-up years" number,
    "linearized rate of infection" text,
    "actuarial freedom from infective endocarditis" text
) ### Response: SELECT MIN("duration of follow-up years") FROM table_204_597