。
People call me Ichi.
Literal
I [topic-は] Ichi [as-で] go-am [explanatory-んだ].
通る in this idiomatic use means 'to pass for, to be known as.' で marks the name as the manner/identity. The ~ている form indicates an ongoing state. イチ is a casual nickname (likely shortening of a longer name like 一郎 or 一二三 — 'one'-based names). んだ adds the explanatory frame.