What rider is on an aprilia that went under 18 laps with a grid total of 17?
CREATE TABLE "125cc_classification" (
  "rider" text,
  "manufacturer" text,
  "laps" real,
  "time_retired" text,
  "grid" real
);
SELECT "rider" FROM "125cc_classification" WHERE "manufacturer"='aprilia' AND "laps"<18 AND "grid"=17;