Frigidaire has recently come out with new error codes, including F13. We'll update our code page shortly.
F13 stands for "Bad EEPROM Identification/Checksum error". If power cycling does not help, replace the electronic oven control. You can enter your oven model number here http://www.appliancepartspros.com/partsearch/
and see price and availability for the control.
Hope this helps.