I don't believe there is anything built in that will do this.
There are lots of programming approaches that will solve the problem, but approaches that I would consider:
1. if your database support stored procedures, you could de-serialize in the procedure and use the procedure to access the data. If the database supports UDFs, you could add the de-serialization code to a function and access the data through a function in a view.
2. create an API that serves up the de-serialized data and use a Tableau Web Data Connector to access it.
Thought about it some more.
You could use TabPy to do the de-serialization inside of Tableau, as long as you're willing to accept the risks of exposing a full programming language.
It's an extremely powerful addition to Tableau, but be certain to read and heed the Security Consideration at the bottom of the Github readme. I run a multi-tenant environment, so can't implement it. The risks would be too high.