Or is it the fourteenth, if you count the War Doctor?
Who knows. BBC likes to confuse it's fans.
Anyway, anyone who's seen the episodes of season 10 can agree that BBC is mean to make us wait till Christmas for the next episode, right?
We can also all agree that the Doctor is definitely going to regenerate soon. And that it's awesome how the First, and possibly more of the Doctors will also be in the next episode.
Well, BBC casted the next Doctor.
Who's ready to see the new Doctor?

Credit to the Verge for this picture.
Our first female Doctor is played by Jodie Whittaker. It's going to be amazing, I just know it.