About the leakage reactance of transformer
Leakage inductance always exists. It is present on the primary winding and the secondary winding. It represents the small percentage of inductance that doesn't magnetically couple to the other coil.

Think about a transformer that has 1:1 turns ratio - which is primary and which is secondary. Of course it doesn't matter so things can't magically be different on one winding compared to the other.