the flag crumpled on the floor is the Ainz Ool Gown flag while the one she looks at afterward is Momonga's.
Though it's never explicitly told that she's is looking at Momonga's flag. Heck, when I first read it, I interpreted it as her looking at her creator's flag. The anime has confirmed she was looking at Momonga's flag though.
Excerpt from the light novel:
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The reason she did not let any maids in the room was to make sure she could monopolize her Ainz dolls and that nobody could touch them. But there was another reason as well.
That was a flag with the emblem of “Ainz Ooal Gown” embroidered on it. The flag which should have been visible as soon as someone entered the room, laid crumpled in a corner of the floor.
There was no sign of admiration or respect towards it, only hatred and hostility.
“Ainz Ooal Gown… How boring.”
In place of the flag of Ainz Ooal Gown, Albedo had raised a different gigantic flag instead. A flag so large, it resembled an opera curtain.
“This, Great Tomb of Nazarick is only yours. I, Albedo wish to only serve you. Ah… One day, I want to hear your great name once again…”
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