Nerode equivalence classes for $ L = \{ a^{n+1}b^m | n,m \geq 0 \text{ and } n+m \text{ is odd} \}$

Question

So actually I have to find the Nerode equivalence classes for two languages. But I'm sure that my solution is correct for the first one.

First language:

$L = ${ $a^nb^m | n,m \geq$ $0$ and $n+m$ is even }

$[\varepsilon] = ${ $a^n | n$ is even }

$[a] = ${ $a^n | n$ is odd }

$[b] = ${ $a^nb^m | n+m$ is odd }

$[bb] = ${ $a^nb^m | n+m$ is even }

$[ba] = ${ $x \in \Sigma^{*} | x$ contained $ba$}

But like I said my problem is the second language:

$ L = ${ $ a^{n+1}b^m | n,m \geq 0 $ and $ n+m$ is odd }

So this is my attempt:

$[\varepsilon] = ${ $a^n | n$ is even }

$[a] = ${ $a^n | n$ is odd }

$[ab] = ${ $x \in \Sigma^{*} | x \in L$}

$[b] = ? $

Im sure that I have mistakes here. I considered the Suffix to find the nerode equivalence classes.

Suff$(\varepsilon) = L$.

Suff$(a) = ${$a^{n+1}b^m | n+m$ is even}

Suff$(ab) = ${$b^m| m$ is even}

Suff$(b) = \emptyset $