Well, leaders come and go. Some are successful and others less successful, both mens and grills. But asking to name "one female leader" who did OK job is not that difficult if you leave aside emotional non-fact based throws like you just did.
Margareth Thatcher / Queen Elisabeth, UK
Indira Gandhi, India
Tarja Halonen, Finland
Gro Brundtland, Norway
and I'm sure the list would go on and on....