Custom query to fetch all entries of a table and that only contains first of many duplicates based on a specific column

I have a Location model and the table looks like

   id |      name      | vin |     ip_address    |         created_at         |         updated_at    ----+----------------+------+---------------+----------------------------+------------------------
    0 | default |    0 | 0.0.0.0/0          | 2021-11-08 11:54:26.822623 | 2021-11-08 11:54:26.822623
    1 | admin  |    1 | 10.108.150.143    | 2021-11-08 11:54:26.82885  | 2021-11-08 11:54:26.82885
    2 | V122  |    122| 10.108.150.122    | 2021-11-08 11:54:26.82885  | 2021-11-08 11:54:26.82885  
    3 | V123 |    123| 10.108.150.123   | 2021-11-08 11:54:26.82885  | 2021-11-08 11:54:26.82885
    4 | V124  |    124| 10.108.150.124   | 2021-11-08 11:54:26.82885  | 2021-11-08 11:54:26.82885
    5 | V122  |    122| 10.108.150.122    | 2021-11-08 11:54:26.82885  | 2021-11-08 11:54:26.82885
    6 | V125  |    122| 10.108.150.125   | 2021-11-08 11:54:26.82885  | 2021-11-08 11:54:26.82885

My method in the Location model

   def self.find_all_non_duplicate
     return self.find(:all, :conditions => "id <> 1")
   end

I want to fetch all entries of the locations table except the entry with id = 1 and that contains only the first entry of many duplicates based on the column ip_address.

Since ip_address of id = 2 and id = 5 is duplicate. I want to keep the first entry of many duplicates i.e., id = 2.

The expected result is

 id |      name      | vin |     ip_address    |         created_at         |         updated_at           ----+----------------+------+---------------+----------------------------+------------------------
 0 | default |    0 | 0.0.0.0/0          | 2021-11-08 11:54:26.822623 | 2021-11-08 11:54:26.822623
 2 | V122  |    122| 10.108.150.122    | 2021-11-08 11:54:26.82885  | 2021-11-08 11:54:26.82885
 3 | V123 |    123| 10.108.150.123   | 2021-11-08 11:54:26.82885  | 2021-11-08 11:54:26.82885
 4 | V124  |    124| 10.108.150.124   | 2021-11-08 11:54:26.82885  | 2021-11-08 11:54:26.82885
 6 | V125  |    122| 10.108.150.125   | 2021-11-08 11:54:26.82885  | 2021-11-08 11:54:26.82885

The entries with id's 1 and 5 to be ignored