Ledian

Ledian's decent bulk and low CP make it useful for minimizing gym degradation, in addition to its resistance against common Fighting-type attackers. That's about it for this Pokemon unfortunately; it doesn't have the stats or movesets to do much else. 

Best PvE Offensive Moveset

• Bug Bite is superior to Struggle Bug on offense.
• Bug Buzz pairs well to fulfill a Bug-type role. 
• Silver Wind is a direct downgrade. 
• Dynamic Punch is a powerful move for attackers, but even better on actual Fighting-type Pokemon. 
• Aerial Ace is useful against Grass-type targets but is a weak move overall. 

Best PvE Defensive Moveset

• Struggle Bug is way better on defense, sporting triple the base power of Bug Bite. 
• Dynamic Punch should be chosen on defense due to its coverage against Ledian's weaknesses. 
• Alternatively Silver Wind is useful for its spammability as a 3-bar move.
• Aerial Ace deals less damage but can be good against opponents who don't switch out their Fighting-type attackers. 
• Bug Buzz doesn't have much merit on defense for a Bug-type. 

Counter is superior to both Bug Bite and Struggle Bug, even without STAB.

Aerial Ace is not an impressive move, but costs the least amount of energy among the available options, and at least gets STAB. Silver Wind ties for the same energy cost, but its coverage is a bit redundant and its stats are poor. Dynamic Punch is recommended for its strong and valuable coverage against the meta. Bug Buzz hits the hardest and demands the most energy for this power, but its coverage is redundant and more niche.