2 KOH + 2 KMnO4 + H2SO3 → H2O + 2 K2MnO4 + H2SO4
This is an acid-base reaction (neutralization): KOH is a base, H2SO3 is an acid.
This is an oxidation-reduction (redox) reaction:
2 MnVII + 2 e- → 2 MnVI (reduction)
SIV - 2 e- → SVI (oxidation)
KMnO4 is an oxidizing agent, H2SO3 is a reducing agent.