Yes, that's the trigger.

FactionType seleucid
Roman.

and EndedInSettlement
Not outdoors.

and RemainingMPPercentage = 100
Stayed still for the entire turn. Might be impossible through movement penalties, as mentioned earlier.

and IsGeneral
Duh.

and SettlementName Syrakousai
Staying in Syracuse.

and I_SettlementOwner Messana = seleucid
and I_SettlementOwner Lilibeo = seleucid
Romans hold the rest of Sicily.

and SettlementBuildingExists > gov4
and SettlementBuildingExists < govparthian
Not client state.

and Attribute Electability < 11
Not already governor of some other place.

and not FactionwideAncillaryExists Governor_of_Sicily
Noone else is governor.