Scotland-raised Gatwa, 29, will be the first Black actor to helm the quintessential British sci-fi show, but he won’t be the first Black Doctor — Jo Martin has played “Fugitive Doctor” in several episodes.Whittaker became the 13th Doctor — and the first woman to play the central galaxy-hopping, extraterrestrial Time Lord who regenerates into new bodies — in 2017, when she took over from Peter Capaldi. Her last episode of “Doctor Who” is expected to air later this year.The original run of “Doctor Who” spanned 1963 to 1989.