I'm having a hard time reading it, partly because the print is old and my eyes are bad, and also because of all the little abbreviations with the lines over them. Those always bug me. On top of that, my Classical Armenian is not that great.
I think the part about Pope Leo is on page 266, just a little more than half way down the first column. Transliterated into English letters, there is a question that seems to go: "Nuzoves uzLevon hertsvadzoghn yev uzbighdz doomarn yoor, zor tryats uzmin hergoos pazhanyal"
VasnTearn can correct my transliteration if it is off. One problem I have with transliterating Classical Armenian is that I do it with the phonology of Modern Western Armenian, which is not that correct for Classical Armenian.
I can recognize a few other names, such as early on there is zArios Agheksantratzin (Arius), and then a bit after that Boghos Samosdatsin, who I think is Paul of Samosata.
It's interesting. Hopefully some day there will be an official and complete translation into English.