What date was there a playoff on the margin of victory during the Shirley Englehorn Invitational?
CREATE TABLE table_13685 (
    "Date" text,
    "Tournament" text,
    "Winning score" text,
    "Margin of victory" text,
    "Runner(s)-up" text
)
SELECT "Date" FROM table_13685 WHERE "Margin of victory" = 'playoff' AND "Tournament" = 'shirley englehorn invitational'
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 date was there a playoff on the margin of victory during the Shirley Englehorn Invitational? ### Input: CREATE TABLE table_13685 (
    "Date" text,
    "Tournament" text,
    "Winning score" text,
    "Margin of victory" text,
    "Runner(s)-up" text
) ### Response: SELECT "Date" FROM table_13685 WHERE "Margin of victory" = 'playoff' AND "Tournament" = 'shirley englehorn invitational'