When dxcc-tv is the call sign how many station types are there?
CREATE TABLE "ibc_tv_stations" (
  "branding" text,
  "callsign" text,
  "ch_num" text,
  "power_k_w" text,
  "station_type" text,
  "location_transmitter_site" text
);
SELECT COUNT("station_type") FROM "ibc_tv_stations" WHERE "callsign"='DXCC-TV';