The FED rear light (which appears to be in your picture) does not have a center bulb. It only utilizes an outer ring of LEDs.
The ROW rear light has a center turn indicator lamp bulb which is a "GE921 capless bulb retained in a bayonet type holder". The ROW have an amber colored center.
However, not knowing exactly why you are inquiring or the particulars of your car, if your DRL are disabled, someone may have retrofitted a rear turn signal bulb in a FED housing with some additional wiring modifications.
Below is a ROW light with bulb housing.