I’ve attended many weddings and performed at a few as well and I have never heard a wedding use Bedrich Smetana’s “Wedding Dance” from his tone poem The Moldau. It is excellent music for a processional because that’s what it is. It is dignified, uplifting music in two—perfect for walking. It can also be easily arranged for piano, string quartet, woodwind quintet, or organ.
Listen to the original for orchestra: