What is the smallest number for Cars per Set built in 1977-1979 larger than 32?
CREATE TABLE "class_253_and_254" (
  "class" text,
  "operator" text,
  "number" real,
  "year_built" text,
  "cars_per_set" real,
  "unit_numbers" text
);
SELECT MIN("cars_per_set") FROM "class_253_and_254" WHERE "year_built"='1977-1979' AND "number">32;