What is the digital terrestria channel number for itv3?
CREATE TABLE "availability_of_channels_from_various_pr" (
  "position" real,
  "channel" text,
  "analogue_terrestrial_channel" text,
  "digital_terrestrial_channel" text,
  "internet" text
);
SELECT "digital_terrestrial_channel" FROM "availability_of_channels_from_various_pr" WHERE "channel"='ITV3';