 He did not win but got the chance to fight the seat again in 1903 at a by-election when the sitting member, Donald Ninian Nicol, died.At the by-election, which was held on 26 August 1903, Ainsworth won in a straight fight against a Unionist candidate, Mr. C Stewart, by a majority of 1,586 votes.Whilst an MP he voted in favour of the 1908 Women's Enfranchisement Bill.