I doubt very much a politician is going to want to make contributions to school fundraisers. That's not their "business". You should ask independent business owners or other individuals who have no political affiliations.
Is it ok for me to send a fundraising email to my mayor's office? We have to raise money for a school sponsored activity. We didn't get enough funding so we have to raise the rest ourselves. Can I send some emails to the mayor's office?
You can send it, but I would doubt very much if you get a response. Community offices don't often donate tax payers money to charities nevermind an unregistered charitable event.
You would probably have better luck going and talking to your mayor face to face and asking him/her directly. If you don't get a donation, you might get some helpful advise on how to raise money in your community.