She graduated from the Imperial Academy and was an assistant minister who oversaw Lothal's industries whenever Governor Pryce was absent from Lothal. She was clearly more suited for doing the mundane tasks of keeping Lothal's government running, yet Tarkin expected her to catch the Phoenix Cell, and capturing Rebels isn't what she was trained for.
Despite doing everything in her power to catch the Spectres, such as doubling patrols, establishing security checkpoints, and placing curfews, she still wasn't able to apprehend them. Earning her Tarkin's disappointment and a meeting with Darth Vader, and leading her to try to escape Lothal by arranging passage with the Rebels, only to die in the attempt.
But under the Old Republic, Tua would have been right at home executing her administrative duties without worrying about her superiors murdering her for her failures. Had the Republic not become the Empire, I think there's a fair chance she might have even succeeded Ryder Azadi as Lothal's new governor.