What class has nsr250 as the machine, with points greater than 97?
CREATE TABLE "motorcycle_grand_prix_results" (
  "year" real,
  "class" text,
  "team" text,
  "machine" text,
  "points" real,
  "rank" text,
  "wins" real
);
SELECT "class" FROM "motorcycle_grand_prix_results" WHERE "machine"='nsr250' AND "points">97;