On the back of the Leonardo board, there is a set of six pins.

Take the wire connected to pin 11 on the Uno and plug it into the middle pin of the pins furthest to the back of the board.

Take the wire connected to pin 12 on the Uno and plug it into the first pin on the set of three pins going toward the board (the pin closest to the Leonardo label).

Finally, take the wire connected to pin 13 on the Uno and plug it into the middle pin of the inner row of three pins.