What is Date, when Type is DS4-4-750, and when Works Number is 74409?
CREATE TABLE "diesel_locomotives" (
  "number" text,
  "builder" text,
  "type" text,
  "date" text,
  "works_number" text
);
SELECT "date" FROM "diesel_locomotives" WHERE "type"='ds4-4-750' AND "works_number"='74409';