CREATE TABLE "ships_operated_by_zeeland_steamship_comp" (
  "ships_name" text,
  "date_entered_service" text,
  "date_withdrawn" text,
  "tonnage" real,
  "type_of_ship" text
);

Question:  what's the date entered service with ships name koningin wilhelmina
SQL: SELECT "date_entered_service" FROM "ships_operated_by_zeeland_steamship_comp" WHERE "ships_name"='Koningin Wilhelmina';

Question:  what's the date where ships name is zeeland entered service
SQL: SELECT "date_entered_service" FROM "ships_operated_by_zeeland_steamship_comp" WHERE "ships_name"='Zeeland';

Question: what is the maximum tonnage where date entered service is 25 march 1986 
SQL: SELECT MAX("tonnage") FROM "ships_operated_by_zeeland_steamship_comp" WHERE "date_entered_service"='25 March 1986';

Question: what are all the date withdrawn for service entered on 21 november 1945
SQL: SELECT "date_withdrawn" FROM "ships_operated_by_zeeland_steamship_comp" WHERE "date_entered_service"='21 November 1945';

Question: what are all the date withdrawn for twin screw ro-ro motorship
SQL: SELECT "date_withdrawn" FROM "ships_operated_by_zeeland_steamship_comp" WHERE "type_of_ship"='Twin Screw Ro-Ro Motorship';

Question: what are all the date withdrawn for koningin beatrix
SQL: SELECT "date_withdrawn" FROM "ships_operated_by_zeeland_steamship_comp" WHERE "ships_name"='Koningin Beatrix';