The deduction you are seeing on your 2019 tax return that says "self-employment" is part of the new Canada Pension Plan Enhancement. There is a maximum allowable claim of $80.85 and is seen on Line 22215 of your tax return.
For more information on this deduction and the changes to your CPP Contributions, please see the following CRA documents:
The Canada Pension Plan enhancement – Businesses, individuals and self-employed: what it means for y...
Line 22215 – Deduction for CPP or QPP enhanced contributions on employment income