WARSAW, July 12 (Reuters) - Poland's incumbent president Andrzej Duda was slightly ahead in Sunday's presidential election, a late poll showed, a narrow victory which if confirmed would allow the ruling nationalists to deepen their conservative reforms.
The late poll combines exit poll data with partial official results.
Duda, an ally of the ruling nationalists Law and Justice (PiS), received 50.8% of the vote, according to the late poll.
Liberal Warsaw Mayor Rafal Trzaskowski, the candidate of the largest opposition party, the centrist Civic Platform (PO), came second with 49.2%. (Reporting by Anna Koper and Alan Charlish; Editing by Daniel Wallis)