Who is the rider where the horse is galan de sauvagere?
CREATE TABLE "table1_18666752_3" (
  "nation" text,
  "rider" text,
  "horse" text,
  "cross_country_penalties" text,
  "total_penalties" text,
  "total_team_penalties" text,
  "team_rank" real
);
SELECT "rider" FROM "table1_18666752_3" WHERE "horse"='Galan De Sauvagere';