(ANSA) - BELGRADE, JUN 18 - Tisza, Hungary's main opposition party, leads Viktor Orbán's ruling ultranationalist party Fidesz by 15%, according to the Medián institute's most recent poll, which was published in the Hungarian newspaper Hvg. According to the new data, Tisza, who is popular among young people and the more educated segments of the population, could receive 51% of the vote. Fidesz is at 28%, while all other parties remain below the 5% threshold required to enter Parliament, with the exception of the far-right party Our Homeland Movement, which is hovering around 4-5%. (ANSA).