what is the name of the designer which the roller coaster had an accident after 1964-05-01?
(AND amusement_parks.ride_designer (JOIN amusement_parks.ride_designer.rides (JOIN (R amusement_parks.accident.ride) (ge amusement_parks.accident.date 1964-05-01^^http://www.w3.org/2001/XMLSchema#date))))