When the engine Ford Cosworth DFV 3.0 v8 has a chassis of m23 and in rounds 14-15, what is its Tyre?
CREATE TABLE "championship_teams_and_drivers" (
  "constructor" text,
  "chassis" text,
  "engine" text,
  "tyre" text,
  "driver" text,
  "rounds" text
);
SELECT "tyre" FROM "championship_teams_and_drivers" WHERE "rounds"='14-15' AND "engine"='ford cosworth dfv 3.0 v8' AND "chassis"='m23';