What's the longitude named zipaltonal fluctus in 1997 with a diameter smaller than 490?
CREATE TABLE "fluctus" (
  "name" text,
  "latitude" text,
  "longitude" text,
  "diameter_km" real,
  "year_named" real
);
SELECT "longitude" FROM "fluctus" WHERE "year_named"=1997 AND "diameter_km"<490 AND "name"='zipaltonal fluctus';