LONDON, Dec 29 (Reuters) - Rebecca Welch is set to become the first female to referee in the FA Cup third round, organisers said on Wednesday. Welch will take charge of Birmingham City"s home tie against Plymouth Argyle, which will be played at St Andrews on Jan. 8, as the first woman referee at that stage of the competition. She became the first female referee to be appointed to an English Football League match in March. Welch has refereed men"s matches in the National League plus elite women"s games including the 2017 FA Cup final.