What was the earliest year that a structure was located in gray court, south carolina?
CREATE TABLE "structures_past_or_present_between_550_a" (
  "pinnacle_height" text,
  "year" real,
  "structure_type" text,
  "main_use" text,
  "country" text,
  "town" text
);
SELECT MIN("year") FROM "structures_past_or_present_between_550_a" WHERE "town"='gray court, south carolina';