CREATE TABLE table_name_98 (date_of_replacement VARCHAR2, date_outgoing VARCHAR2)

When did the manager take over for the manager that left on August 20, 2008?
SELECT date_of_replacement FROM table_name_98 WHERE date_outgoing = "august 20, 2008"
SELECT "date_of_replacement" FROM "table_name_98" WHERE "august 20, 2008" = "date_outgoing"