From A Wiki of Ice and Fire
|Book(s)|| A Clash of Kings (mentioned)|
A Storm of Swords (appears)
A Feast for Crows (appendix)
A Dance with Dragons (appendix)
A Clash of Kings
Long Lew is on duty at the River Gate when Ser Jaime Lannister tries to escape from Riverrun. The escape is only stopped because he sees that Ser Edmure Tully is returning in a boat, so Edmure could not be below giving orders to open the gate.