apt - ubuntu 14.04 node porridge

I have two versions of nodejs on my machine.

I had only v8.6.0. I ran:

sudo apt-add-repository "deb https://deb.nodesource.com/node_8.x $(lsb_release -sc) main"
sudo apt-get update
sudo apt-get install nodejs

And received message: "Installing v8.12.0"

Following this, output of "apt list -a node":

Listing... Done
nodejs/unknown,now 8.12.0-1nodesource1 amd64 [installed]
nodejs/unknown 6.14.4-1nodesource1 amd64
nodejs/trusty-updates,trusty-security 0.10.25~dfsg2-2ubuntu1.2 amd64

nodejs/trusty 0.10.25~dfsg2-2ubuntu1 amd64

But "node -v" still gives:

v8.6.0

"relevant" lines from /etc/apt/sources.list:

deb http://security.ubuntu.com/ubuntu trusty-security main restricted
deb-src http://security.ubuntu.com/ubuntu trusty-security main restricted
deb http://security.ubuntu.com/ubuntu trusty-security universe
deb-src http://security.ubuntu.com/ubuntu trusty-security universe
deb http://security.ubuntu.com/ubuntu trusty-security multiverse
deb-src http://security.ubuntu.com/ubuntu trusty-security multiverse

deb https://deb.nodesource.com/node_8.x trusty main

I even have this in /etc/apt/sources.list.d/nodesource.list:

deb https://deb.nodesource.com/node_6.x trusty main
deb-src https://deb.nodesource.com/node_6.x trusty main
deb https://deb.nodesource.com/node_6.x trusty main
deb-src https://deb.nodesource.com/node_6.x trusty main

I guess I have a conflict with Ubuntu's repo and nodesource's?

How to resolve?