What date was proposed when the listed date was 12/16/1994 in the County of beaufort?
CREATE TABLE "superfund_sites" (
  "cerclis_id" text,
  "name" text,
  "county" text,
  "proposed" text,
  "listed" text
);
SELECT "proposed" FROM "superfund_sites" WHERE "listed"='12/16/1994' AND "county"='beaufort';