What is Fonsi Nieto's average grid when he's riding a Suzuki GSX-R1000?
CREATE TABLE "superbike_race_1_classification" (
  "rider" text,
  "bike" text,
  "laps" real,
  "time" text,
  "grid" real
);
SELECT AVG("grid") FROM "superbike_race_1_classification" WHERE "bike"='suzuki gsx-r1000' AND "rider"='fonsi nieto';