How to return value for key from a jsonb column?
This post gives you your answer:

CREATE TABLE json_test 
(
  id serial primary key,
  data jsonb
);
INSERT INTO json_test (data) VALUES ('{"0":"INVALID","1":"BELOW","2":"EQUAL","3":"ABOVE"}');


You specify the element that you wish to extract thus:

SELECT id, data-&gt;&gt;'1' AS whatever FROM json_test;


And the result is:

id      whatever
1       BELOW


There are a shedload of new json functions in PostgreSQL - there could be more examples (hint PostgreSQL team...).