The native Hoenn Pokédex in Pokémon Ruby, Sapphire & Emerald features 202 Pokémon, 135 of which are new. It puts the Hoenn starters at the beginning and groups evolutions from different generations together.
Later a National Dex is obtained with the entire set of Pokémon in the order they were added. Our Ruby/Sapphire Pokémon stats page shows just the new Pokémon introduced in Gen 3.