Depending on where you are trying to extract it...
| rex "^(?:(\"[^\"]*\"|[^,]*),){10}(?<myelevens>\"[^\"]\"|[^,]*),"
For an index-time extraction, I'd have to verify the escaping and capture-marking. I believe that, without the outside quotes and the capture-name, that regex will work and the capturing group you want will be \2, but I'd have to test it to be sure.
EXPLANATION IN ENGLISH OF THE REGEX
Here's the working parts of that regex:
This part, if it encounters a quote, will take everything to the next quote. Since we are throwing the match away, I didn't worry about whether or not we kept the quotes themselves... we kept them. We will want to make sure that that part goes first anyplace there could be a quoted string, both at the beginning and after every comma.
\"[^\"]*\"
This alternate part grabs anything there that isn't a comma, we will use it wherever the first part fails.
[^,]*
Now we group those as alternates (___|___) , and we'll use them between the commas.
(\"[^\"]*\"|[^,]*)
Anchor the start of the string ^, grab the comma afterward ,, group it in a noncapturing group (:?) and repeat the whole group 10 times {10} --- ^(?:___,){10}
^((\"[^\"]*\"|[^,]*),)
That whole mess gets rid of everything through the first ten commas. Now we'll just repeat the same unit, but get rid of that colon to make it capturing and add the capture name <myelevens> ---
(?<myelevens>\"[^\"]\"|[^,]*),
