What is the Time when there are 18 laps, grid larger than 15, and Rider of Russell Holland?
CREATE TABLE "superbike_race_1_classification" (
  "rider" text,
  "bike" text,
  "laps" real,
  "time" text,
  "grid" real
);
SELECT "time" FROM "superbike_race_1_classification" WHERE "laps"=18 AND "grid">15 AND "rider"='russell holland';