CREATE TABLE Project_Staff (role_code VARCHAR, date_from VARCHAR)

How many project staff worked as leaders or started working before '1989-04-24 23:51:54'?
SELECT COUNT(*) FROM Project_Staff WHERE role_code = 'leader' OR date_from < '1989-04-24 23:51:54'
SELECT COUNT(*) FROM "Project_Staff" WHERE "date_from" < '1989-04-24 23:51:54' OR "role_code" = 'leader'