The Governor shall be elected by the qualified voters of the Commonwealth at the time and place of choosing members of the General Assembly. Returns of the election shall be transmitted, under seal, by the proper officers, to the State Board of Elections, or such other officer or agency as may be designated by law, which shall cause the returns to be opened and the votes to be counted in the manner prescribed by law. The person having the highest number of votes shall be declared elected; but if two or more shall have the highest and an equal number of votes, one of them shall be chosen Governor by a majority of the total membership of the General Assembly. Contested elections for Governor shall be decided by a like vote. The mode of proceeding in such cases shall be prescribed by law.