What is the chassis for offy engine and 25th finish?
CREATE TABLE "indy_500_results" (
  "year" real,
  "chassis" text,
  "engine" text,
  "start" text,
  "finish" text,
  "entrant" text
);
SELECT "chassis" FROM "indy_500_results" WHERE "engine"='offy' AND "finish"='25th';