[Lord_Bob]

10 Heavy Infrantry+Indie Commander vs 20 PD
6 Heavy Infrantry+8 Archers+Indie Commander vs 20 PD
8 guys with tower shields/decent armour vs 20 PD
12 Castle Archers(10 morale) vs 20 PD

This is without proper battle locations.

But with luck, just about anything can beat monkey PD.