Who directed the episode written by Matt Ford?
CREATE TABLE "table1_18712423_3" (
  "series_episode" real,
  "season_episode" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text,
  "viewers_millions" text
);
SELECT "directed_by" FROM "table1_18712423_3" WHERE "written_by"='Matt Ford';