The most used defense against this charge would likely be self-defense or claiming the attack was made under duress. Few other defenses would work against this charge.
You were defending yourself, if they attacked you first or had a potential weapon in their hands. They threatened harm to you. There were multiple individuals approaching.
The most common defense against any charge is ignorance. I was not present at the time. I was not near the scene. I was with someone else at the time. I think you have me mistaken for someone else.