What is the difference between 举办 and 举行？

举办 and 举行 both Verbs mean "to organize an event", and "to hold an activity".

Difference 1:
举办 emphasis on the process of handling and organizational process.
举行 emphasis on conducting a ceremonious event in a formal or prescribed manner.
eg:
他们要举办舞会。（They are going to arrange or organize a party.）
他们要举行舞会。(They are going to have a party.)

Difference 2:
举办 + 晚会/比赛/讲座/运动会/交易会......
举行 + 谈判/会议/会谈/集会/典礼/宴会/发布会......

Difference 3:
举办 + nominal object
举行 + nominal object or verbal object
eg:
举办婚礼
举行婚礼
举行游行示威