How to ensure redundancy of a polling process

I need to poll a database table (DB2) using Python. The table gets updated quite frequently so I am not particularly worried about empty pings. I wanted to get some tips around how to ensure redundancy for such a polling process. If I have only one process (let's call it A) then there is no backup in case A fails. If I create two processes A&B then how do I ensure that only one process is polling the database at a time and the other process kicks in only if the first one fails.

I understand this question is too broad, however, I would appreciate any pointers about the latest design patterns or frameworks that will help me achieve redundancy. I can use Java instead of Python if it will work better.