Out of the few Pokemon with No Guard, Doublade technically has the highest sum of defensive stats, (HP, Def, Sp. Def). However, this is because of Doublade's Defense stat of 150. Doublade's combined total is 258, (59+150+49).
If you're looking for something a little more balanced, Machamp is your best bet. With a combined total of 255, (90+80+85), Machamp is your all around best Defensive Pokemon with No Guard.
No Guard (PokemonDB)
Hope I could help!
