what are all the date withdrawn for twin screw ro-ro motorship
CREATE TABLE "ships_operated_by_zeeland_steamship_comp" (
  "ships_name" text,
  "date_entered_service" text,
  "date_withdrawn" text,
  "tonnage" real,
  "type_of_ship" text
);
SELECT "date_withdrawn" FROM "ships_operated_by_zeeland_steamship_comp" WHERE "type_of_ship"='Twin Screw Ro-Ro Motorship';