Mr Doanab, 51, beat competition from two others to win the slot.
The seat, only annexed by the NPP in the 2012 elections, was abdicated by Robert Nachinab Mosore after he was enskinned Paramount Chief of Tongo.
Mr Doanab polled 182 votes out of a total of 399 to win his party’s primary, held on Sunday, June 21.
Placing second and third respectively are Robert Ayinaba Alibo with 119 votes and William Zuuga with 96 votes. Two ballots were spoilt.
Our Upper East Region correspondent reports that the elections were devoid of violence.
TV3’s Rabiu Tanko Mohammed reported that the vanquished promised to work together with the victor to retain the seat for the NPP.
The Electoral Commission of Ghana set the by-elections for Tuesday, July 7 after it was notified of the resignation of Mr Mosore, who was in Parliament last Friday to bid the House farewell.