What was the first area code in the USA to have a middle digit other than 0 or 1?

In 1947, the USA was divided into 86 different telephone area codes, which were defined as having three digits, with the middle digit being 0 or 1, as these numbers were not used in the previous assignment of two-digit area codes. At first, area codes with the middle digit 0 were assigned to a plan area that comprised an entire state, but states with multiple numbering plan areas received area codes having 1 as the second digit. Eg Oregon was assigned 503, but California received 213, 415, and 916.

After valid area codes were used up by expansion, there was a need to allow the digits 2 through 8 to be used as a middle digit in new area code assignments (with 9 being reserved for even more future expansion). "The first area codes without a 1 or 0 as the middle digit were area code 334 in Alabama and area code 360 in Washington, which both began service on January 15, 1995. This was followed quickly by area code 520 serving Arizona on March 19, 1995'.

https://en.wikipedia.org/wiki/Original_North_American_area_codes
https://en.wikipedia.org/wiki/North_American_Numbering_Plan