Lugia has a higher base speed than ho oh. With max special attack and speed(with a speed boosting nature) it can easily fire off a hydro pump that would be a 2 to 3 hit KO depending on the Ho oh`s special defense and HP investment. If the Ho oh was invested in speed and attack it could still take a hydro pump and hit back with STAB sacred fire, which could possibly be a 2 hit KO if the Lugia has no investment in defense or HP. Keep in mind tho that most Lugia are defense meaning they could take at least 2 or 3 sacred fires. Lugia could also use ancient power, which would be a 2 hit KO to almost all Ho oh.

Overall there are a ton of factors to consider, even if this was just a one on one match. Id put my money on Lugia though.

And in the anime Lugia would probably win too

Lugia. Not only am I more familiarized with him from the second movie (My favorite os the series), but you rarely ever get a physic/flying matchup, whereas there are constant fire/flying matchups (Charizard, Moltres, Ho-Oh).

But really, it's different for everyone, different strokes for different folks.

lugia 'cuz it can fly

Mewtwo