How many champions are shown for the runner-up of stefan edberg?
CREATE TABLE table_21584646_10 (
    champion VARCHAR,
    runner_up VARCHAR
)
SELECT COUNT(champion) FROM table_21584646_10 WHERE runner_up = "Stefan Edberg"
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: How many champions are shown for the runner-up of stefan edberg? ### Input: CREATE TABLE table_21584646_10 (
    champion VARCHAR,
    runner_up VARCHAR
) ### Response: SELECT COUNT(champion) FROM table_21584646_10 WHERE runner_up = "Stefan Edberg"