How many channel tv (dt)s are in austin, texas?
CREATE TABLE "stations" (
  "city_of_license_market" text,
  "station" text,
  "channel_tv_dt" text,
  "owned_since" text,
  "primary_affiliation" text
);
SELECT COUNT("channel_tv_dt") FROM "stations" WHERE "city_of_license_market"='Austin, Texas';