Question: Who was in charge of the country where Uvac was located?

full_context: Document 1: President of Russia: The president is elected directly through a popular vote to a six - year term. The law prohibits anyone from ever being elected to the presidency for a third consecutive term. In all, three individuals have served four presidencies spanning six full terms. On 7 May 2012, Vladimir Putin became the fourth and current president.
Document 2: Danube: The Danube was once a long - standing frontier of the Roman Empire, and today flows through 10 countries, more than any other river in the world. Originating in Germany, the Danube flows southeast for 2,850 km (1,770 mi), passing through or touching the border of Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, Moldova and Ukraine before draining into the Black Sea. Its drainage basin extends into nine more countries. The Danube river basin is home to fish species such as pike, zander, huchen, wels catfish, burbot and tench. It is also home to a large diversity of carp and sturgeon, as well as salmon and trout. A few species of euryhaline fish, such as European seabass, mullet, and eel, inhabit the Danube delta and the lower portion of the river.
Document 3: Portugal: The Head of State of Portugal is the President of the Republic, elected to a five-year term by direct, universal suffrage. He or she has also supervision and reserve powers. These powers are often compared[by whom?] with the "moderator power" that was held by the King in the Portuguese Constitutional Monarchy.[citation needed] Presidential powers include the appointment of the Prime Minister and the other members of the Government (where the President takes into account the results of legislative elections); dismissing the Prime Minister; dissolving the Assembly of the Republic (to call early elections); vetoing legislation (which may be overridden by the Assembly with a supermajority); and declaring a state of war or siege. The President is also the ex officio Commander-in-Chief of the Armed Forces.
Document 4: Sugovica: The Sugovica is a small river in southern Hungary, near Baja. It is also known as "Kamarás-Duna". The Sugovica is an old tributary of the Danube.
Document 5: Uvac: The Uvac () is an international trans-boundary river, rising under Golija mountain and Pešter plateau, then flowing through southwestern Serbia and cross into eastern Bosnia and Herzegovina where, after 115 km, finally meets the Lim river from the right, however, before it empties into the Lim, for a 10 kilometers Uvac forms the border between two countries. Also, while meandering through Serbia, Uvac loosely makes the northern border of the Raška region too.
Document 6: President of South Africa: The President is elected by the National Assembly, the lower house of Parliament, and is usually the leader of the largest party, which has been the African National Congress since the first non-racial elections were held on 27 April 1994. The Constitution limits the president's time in office to two five - year terms. The first president to be elected under the new constitution was Nelson Mandela. The incumbent is Cyril Ramaphosa, who was elected by the National Assembly on 15 February 2018 following the resignation of Jacob Zuma.
Document 7: Montana: The northern section of the Divide, where the mountains give way rapidly to prairie, is part of the Rocky Mountain Front. The front is most pronounced in the Lewis Range, located primarily in Glacier National Park. Due to the configuration of mountain ranges in Glacier National Park, the Northern Divide (which begins in Alaska's Seward Peninsula) crosses this region and turns east in Montana at Triple Divide Peak. It causes the Waterton River, Belly, and Saint Mary rivers to flow north into Alberta, Canada. There they join the Saskatchewan River, which ultimately empties into Hudson Bay.
Document 8: Portugal: The President, who is elected to a five-year term, has an executive role: the current President is Aníbal Cavaco Silva. The Assembly of the Republic is a single chamber parliament composed of 230 deputies elected for a four-year term. The Government is headed by the Prime Minister (currently António Costa) and includes Ministers and Secretaries of State. The Courts are organized into several levels, among the judicial, administrative and fiscal branches. The Supreme Courts are institutions of last resort/appeal. A thirteen-member Constitutional Court oversees the constitutionality of the laws.
Document 9: Mali: The president serves as a chief of state and commander in chief of the armed forces. A prime minister appointed by the president serves as head of government and in turn appoints the Council of Ministers. The unicameral National Assembly is Mali's sole legislative body, consisting of deputies elected to five-year terms. Following the 2007 elections, the Alliance for Democracy and Progress held 113 of 160 seats in the assembly. The assembly holds two regular sessions each year, during which it debates and votes on legislation that has been submitted by a member or by the government.
Document 10: Ravne, Litija: Ravne () is a small settlement in the hills above the right bank of the Sava River northwest of Gabrovka in the Municipality of Litija in central Slovenia. Traditionally the area was part of Lower Carniola and is now included with the rest of the municipality in the Central Sava Statistical Region.
Document 11: Baranya County: The county lies in southern Hungary, on the border with Croatia. The River Drava forms part of its southern border, and the River Danube its eastern border. It shares borders with the Hungarian counties Somogy, Tolna, and Bács-Kiskun. The capital of Baranya county is Pécs.
Document 12: Tomislav Nikolić: Tomislav Nikolić (, ; born 15 February 1952) is a Serbian politician who served as the President of Serbia from 2012 to 2017. He is also the founder of the Serbian Progressive Party, and he led the party until his election as President. In the 2012 presidential election, he was elected to a five-year term as President in a second round of voting.
Document 13: Gajeva planina: Gajeva planina (Serbian Cyrillic: Гајева планина) is a mountain on the border of Serbia and Bosnia and Herzegovina, between towns of Priboj and Rudo. Its highest peak "Timor" has an elevation of above sea level.
Document 14: Northeast (Vietnam): The northern part junction with Vietnam-China border are the plateau (highland) turns from west to east are: Bắc Hà, Quản Bạ, Đồng Văn. Two first plateau has an average elevation of 1000-1200m. Đồng Văn Plateau is 1600m. River and stream flowing through the plateau created a long and deep canyons. There are also some small plain, which is Thất Khê, Lạng Sơn, Lộc Bình, Cao Bằng.
Document 15: Serbia: The President of the Republic ("Predsednik Republike") is the head of state, is elected by popular vote to a five-year term and is limited by the Constitution to a maximum of two terms. In addition to being the commander in chief of the armed forces, the president has the procedural duty of appointing the prime minister with the consent of the parliament, and has some influence on foreign policy. Aleksandar Vučić of the Serbian Progressive Party is the current president following the 2017 presidential election. Seat of the presidency is Novi Dvor.
ground_truth: Aleksandar Vučić
sub_queries: Uvac >> country Answer: Serbia
Who was in charge of Serbia ? Answer: Aleksandar Vučić