There are 3 tables :
PERSONS (personID PRIMARY KEY, firstName, lastName)
EMPLOYEES (employeeID PRIMARY KEY, personID FOREIGN KEY)
OVERTIME (overtimeID PRIMARY KEY, employeeID FOREIGN KEY
supervisorID)

In 1 query, I wish to retrieve the names of all employee's
who filed for overtime as well as the names of their supervisors.
Ideally, you can get the names of supervisors from PERSONS table.
The problem is that you can also get the names of the employees
from the PERSONS table. How do i go about this problem?

You can join the same table twice using this syntax

INNER JOIN Table AS Table_1 ON Table_1.id = OtherTable.id
INNER JOIN Table AS Table_2 ON Table_2.id = AnotherTable.id