CREATE TABLE "londonderry_and_lough_swilly_railway" (
  "type" text,
  "fleet_numbers" text,
  "quantity_made" real,
  "manufacturer" text,
  "date_made" text,
  "date_withdrawn" text
);

Question: What is the date made that has an associated fleet number of 4?
SQL: SELECT "date_made" FROM "londonderry_and_lough_swilly_railway" WHERE "fleet_numbers"='4';

Question: What is the withdrawal date associated with a date made of 1904?
SQL: SELECT "date_withdrawn" FROM "londonderry_and_lough_swilly_railway" WHERE "date_made"='1904';