Conversation so far:
Who were the original three ninja turtles?
CANNOTANSWER.
What were the names of the Ninja Turtles?
Teenage Mutant Ninja Turtles.
Did they have a leader?
In The Secret of the Ooze, Leonardo was much more prominent and his leader position was brought to focus.

Question: Who did he lead?
Self-contained rewrite: Who did Leonardo lead?