I don’t think that the remaining bits of the 1831 census for Co Derry are on line in one batch. At least I have never found them. I have a copy of the section for Dunboe Parish only, and can tell you that there are no Todds on it.
A copy of the remaining bits of the census is held at PRONI and I believe Coleraine Library has a copy too but as far as I know you need to get someone to look them up for you. Alternatively I have seen messages on the Rootschat site http://rootschat.com/
which suggests that some of their members may have access to copies. I suggest you try asking there.
The 1831 isn’t quite as comprehensive as subsequent censuses. What it records is the name of the owner/occupier, his/her sex, the number of servants and their sex, the total number of people in the household and the numbers of each religious denomination. So you don’t get names of all the family, their relationship to head of household nor any ages.