Question about the miniseries, Superman Presents the Phantom Zone

I just finished the first issue of this (what I think is regarded as a) bronze age miniseries. In it we follow one of the main protagonists, Charlie Kweskill. Superman mentions at the end of the first issue that Charlie was originally a Kryptonian who was wrongly sentenced to the Phantom Zone and much later Superman helped release him as well as helped Charlie start a new life on earth. There was no editorial "see this issue" note. I was wondering if anyone knew of the Action or Superman issue that this backstory occurred, or if it was simply a narrative throwaway callback for this issue only to falsely reinforce the story within "The Phantom Zone?" Any help would be much appreciated. Thanks in advance.

[url]https://en.m.wikipedia.org/wiki/Quex-Ul[/url]

Wikipedia says he debuted in Superman #157