The Leona build for Support is Locket of the Iron Solari and Aftershock. This LoL Leona guide for Support at Platinum+ on 13.23 includes runes, items, skill order, and counters.
51.8%
(+0.9%)
44.8%
(+0.2%)
5.4%
(+0.4%)
3.5%
(-0.5%)
247
(-7)