What is the custody level of the facility in Shelton?
CREATE TABLE "current_prisons" (
  "facility" text,
  "location" text,
  "year_opened" text,
  "major_facility" text,
  "population_gender" text,
  "capacity" real,
  "custody_level_s" text
);
SELECT "custody_level_s" FROM "current_prisons" WHERE "location"='Shelton';