The mirror-universe Leeta is a Bajoran member of the Terran Rebellion on Terok Nor, seen in The Emperor's New Cloak, where she ends the story in the company of the mirror Ezri.
The mirror counterpart of Leeta appears in the seventh-season episode The Emperor's New Cloak, played like the original by Chase Masterson. In this universe she is not a dabo girl married to Rom but a fighter in the Terran Rebellion based on Terok Nor.
She is among the rebels who deal with Quark and Rom when the two Ferengi cross over with a stolen Klingon cloaking device, and Rom is visibly thrown by meeting a version of his wife who has no idea who he is.
After the Regent's flagship has been captured she approaches the mercenary Ezri Tigan, who has just lost her lover Brunt and broken with the Intendant, and the two leave together.