Who was the vacator when the date successor seated was august 21, 1973?
CREATE TABLE table_72177 (
    "District" text,
    "Vacator" text,
    "Reason for change" text,
    "Successor" text,
    "Date successor seated" text
)
SELECT "Vacator" FROM table_72177 WHERE "Date successor seated" = 'August 21, 1973'
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: Who was the vacator when the date successor seated was august 21, 1973? ### Input: CREATE TABLE table_72177 (
    "District" text,
    "Vacator" text,
    "Reason for change" text,
    "Successor" text,
    "Date successor seated" text
) ### Response: SELECT "Vacator" FROM table_72177 WHERE "Date successor seated" = 'August 21, 1973'