Retirement tax questions

You are actually already deducting it when you enter the W-2. The amount in Box 1 Wages of the W-2 is reduced due to contributing the retirement plan. 

You do not enter it anywhere else in TurboTax. 

Law Enforcement Officers' and Fire Fighters' Retirement System (LEOFF).

LEOFF Plan 2 is a 401(a) defined benefit plan. When you retire, you will receive a monthly benefit for the rest of your life that is based on your years of public service and your Final Average Salary (FAS).