I agree with this statement. Without continously learning, there's no way one can know what leadership is all about.
First of all, leadership isn't only a definition for knowing how to order around, it is about knowing how to lead other people on the good path, making them learn what you already know.
Secondly, as a leader, you can learn a lot of things as well, passing your knowledge to your team.
Leadership and learning truly are indispenable to each other.