In AWS CLI the correct way to reach any configured service, is to mention the correct service description. The subnet syntax is not so correct so use the one mentioned below:
aws--region us east-1 elb describe-load-balancers --query 'LoadBalancerDescriptions[?contains(Subnets, `subnet-1234546`)==`true`].LoadBalancerName' --output text
for more CLI relateded issues check this- https://www.edureka.co/blog/aws-cli/
I hope this helps you