It was sometimes used for the 10th Doctor, once used in Hell Bent for the 12th Doctor , and even once used in Class. Although it actually could have been the 9th Doctor in that scene from Class where it was used - who knows? Who nose... If you ever forget which one it is, it's the one that goes "Ooooooooooooohh ooooooooooh ooooh~". Basically I Am The Doctor for the RTD Era.