I take it you are referring to Jordans brief control of East Jerusalem which they lost as a result of their unsuccessful invasion in 1967. Israels sovereignty over Jerusalem existed 2000 years before Jordan existed and they have had sovereignty 45 years now compared to Jordans 19 years of control
No, it isn't. And it doesn't matter if you try to slap the term "legally" onto the statement.
Jerusalem has never been under "Palestinian" control. They have no claim to it, whatsoever.