Foden has 24 goals for City in all competitions this season and has often been utilised in more central roles by coach Pep Guardiola
Bangladesh won its last gold medal in swimming in the 2006 edition of the games.
Mahfuza clocked 1 minute 17.86 seconds to finish the fastest in Guwahati, India on Sunday.
Pakistan's Lianna Catherine Swan won silver, with a timing of 1 minute 18.58 seconds. India's Chahat Arora took bronze with 1 minute 18.77 seconds.
In the last 11 editions of the South Asian Games, Bangladesh hauled a total of 63 gold medals and 15 of them had come from swimming events.
Bangladeshi swimmers had a tally of six silver medals and 10 bronzes in the 2010 games in their own backyard.