Is there a way to delete duplicate from a cell value (value of a given row and column) using Postgresql In my Postgres db, I have a table with some columns where one column B has values as follows: 

A      B
a1     b0, b1, b1
a2     b2, b3
a3     b4, b4, b5, b5


My expected output should be like this: 

A      B
a1     b0, b1
a2     b2, b3
a3     b4, b5


Is there a simple UPDATE postgresql to do this task?
Assuming b is an array:

UPDATE mytab
SET b = (SELECT array_agg(DISTINCT x)
         FROM unnest(b) AS x);