For a professional, dedicated daycare, it is absolutely inappropriate.
For in-home daycares, though, it may be difficult to avoid.
As Dave mentioned in his answer, the clear recommendation is that there should be no television exposure before the age of two, and after that the amount of television exposure, if any, should be heavily restricted.
Unfortunately, most people do not seem to follow this. It is very common (at least in my experience) for people to sit infants and toddlers in front of a television to quiet them down.
This can potentially put you in the minority when dealing with private in-home daycare options, particularly if there is a mixed age range.
Our current in-home daycare, which is fully licensed, is a small group of mixed-age children spending the day in the provider's home. They do have a television which is usually running children's shows or movies in the background throughout the day. I was not happy when I found that out, but literally the only other option open to us at the time was a religious daycare offered by a faith I do not personally subscribe to.
Over a year later, we're still with the same daycare, and I've been relieved to find that the television has not become a problem. When I pick my son up, he isn't glued to the television. When I drop him off, he doesn't run to watch the TV. Instead, he plays with the other children, and largely ignores the TV.
It's still not ideal, and again, I would absolutely expect that any dedicated daycare or preschool not make a TV even an option. However, if you do find a highly recommended in-home practice, there is a decent chance that a TV will be used.